CN112747868B - Air tightness detection method - Google Patents
Air tightness detection method Download PDFInfo
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- CN112747868B CN112747868B CN202110102504.4A CN202110102504A CN112747868B CN 112747868 B CN112747868 B CN 112747868B CN 202110102504 A CN202110102504 A CN 202110102504A CN 112747868 B CN112747868 B CN 112747868B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
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Abstract
The invention provides an air tightness detection method, which comprises the following steps: s1, sealing one end of a through hole of a workpiece to be tested by adopting a sealing element, placing an air bag sealed with trace gas in the through hole, and welding the other end of the through hole; s2, performing first air leakage detection on the workpiece to be detected; s3, destroying the sealing element, and performing secondary air leakage detection on the workpiece to be detected; s4, collecting results of the first air leakage detection and the second air leakage detection; and S5, removing the sealing element, collecting the state information of the air bag and judging the air tightness of the through hole. The trace gas is sealed in the air bag and placed in the through hole, and the air bag is damaged while welding and sealing, so that the trace gas is sealed in the through hole, the through hole inflation process is simplified, and the detection efficiency is improved. The invention can determine whether the air bag is damaged or not and whether the through hole is filled with the tracer gas or not by detachably sealing and detecting the air leakage again, thereby preventing the detection leakage caused by the fact that the air bag is not damaged.
Description
Technical Field
The invention relates to the technical field of air tightness detection, in particular to an air tightness detection method of a through hole.
Background
Lithium batteries are receiving attention due to their advantages of high energy density, high output power, long charge/discharge life, fast charge, green and pollution-free properties, wide operating temperature range, and low self-discharge.
The chemical system in the lithium battery is active in property, and the lithium battery is very easy to generate side reaction with external moisture and air to cause the performance degradation or the failure of the battery, so that the packaging airtightness is very important for the reliability and the safety of the lithium battery. How to effectively detect the air tightness of the lithium battery and ensure that packaging defective products cannot flow into the consumer market has very important significance.
At present, partial square lithium battery can use the plug to seal the liquid injection port after injecting liquid, and the liquid injection port is a through hole. The liquid filling port is closed to ensure that the inside of the battery keeps a certain vacuum degree, and then a repair welding sheet is welded above the liquid filling port by laser to implement sealing. Because the leakproofness of plug leads to the unable space that gets into between plug and the aluminum sealing sheet of the inside tracer gas of pouring into the battery in advance to the welding gas tightness of aluminum sealing sheet can't be detected.
Helium detection is the highest known precision air tightness detection means at present, and at present, the square aluminum shell battery cannot detect the air tightness after welding of the liquid injection port because the helium does not directly contact with the sealing repair welding sheet of the liquid injection port due to the existence of the sealing rubber plug. Because can't detect and annotate liquid mouth welding aluminum sheet and whether accomplished sealedly, and electrolyte is after releasing lithium ion and pole piece take place chemical reaction, can produce complicated gas, lead to battery internal pressure big. And the electrolyte is corrosive, so the sealing performance of the rubber plug can be changed due to aging and other problems, and the rubber plug cannot be completely sealed. At the moment, if the welding aluminum sheet of the liquid injection port is not completely sealed, water molecules enter the inside of the battery to cause short circuit and failure, and the battery is scrapped, even the possibility of leakage, combustion, explosion and the like exists. Therefore, how to accurately detect the sealing performance of the liquid filling opening welded seal becomes an urgent problem to be solved.
Disclosure of Invention
In view of the above, it is necessary to provide a method for detecting the airtightness of the existing welding.
In order to achieve the purpose, the invention adopts the following technical means:
a method for detecting air tightness comprises the following steps:
s1, sealing one end of a through hole of a workpiece to be tested by adopting a sealing element, placing an air bag sealed with trace gas in the through hole, and welding the other end of the through hole;
s2, performing first air leakage detection on the workpiece to be detected;
s3, loosening the sealing element to enable the end face not to have sealing performance, and performing secondary air leakage detection on the workpiece to be detected;
s4, collecting results of the first air leakage detection and the second air leakage detection;
and S5, removing the sealing element, collecting the state information of the air bag and judging the air tightness of the welding and sealing position of the through hole.
Preferably, the through hole comprises a liquid injection port and a liquid injection hole; the liquid injection port is sealed by welding, and the liquid injection hole is sealed by adopting a sealing element.
Preferably, the method for judging the air tightness of the through hole sealing part comprises the following steps:
if the trace gas is not detected in the first gas leakage detection and the same workpiece is subjected to second gas leakage detection, namely only the end face of the liquid injection hole is damaged, namely the trace gas is detected after the sealing state of the sealing piece end is damaged, the gas tightness of the welding and sealing position of the through hole is good;
if trace gas is detected in the first gas leakage detection, the air tightness of the through hole welding seal is poor;
if the trace gas is not detected in the first gas leakage detection, the trace gas is not detected in the second gas leakage detection, and the airbag is not broken, the airtightness of the through hole weld seal can not be judged, and the steps S1-S5 are repeated.
Preferably, the tracer gas is selected from at least one of nitrogen, hydrogen, helium, neon, argon, krypton, xenon, or radon.
Preferably, the material of the air bag is selected from composite materials formed by one or more of PP, PE, PVC or PS.
Preferably, the repair welding piece adopted by the welding seal comprises a metal repair welding piece or a plastic repair welding piece.
Preferably, the metal patch welding piece comprises one of an aluminum welding piece, an iron welding piece or a copper welding piece.
Preferably, the seal comprises a glue, gel, staple or plug seal.
Preferably, the method of air leak detection comprises helium detection.
Compared with the prior art, the invention has the following technical effects:
the trace gas seal and the air bag are arranged in the through hole, and the trace gas is sealed in the through hole while welding, so that the process of inflating the through hole is simplified, and the detection efficiency is improved.
The invention can determine whether the air bag is damaged or not and whether the through hole is filled with the tracer gas or not by detachably sealing and detecting the air leakage again, thereby preventing the detection leakage caused by the fact that the air bag is not damaged.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 shows a schematic view of a square lithium battery cover;
fig. 2 shows a schematic view of a square through hole of a lithium battery cover.
Description of the main element symbols:
1-a square lithium battery cover; 2-liquid injection port; 3-air bag; 4-repair welding sheet; 5-a rubber plug; 6-liquid injection hole.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
The existing airtight detection mode of the lithium battery is to inject helium gas after the battery is injected with liquid, plug a rubber plug 5 at a liquid injection hole 6 and then put airtight detection equipment for airtight detection.
Usually, plug 5 is filling in after the liquid hole is annotated, because plug 5 is elastic, so there is stress release, and this moment, plug 5 can be filled very tightly, and the leakage quantity is extremely little, so when annotating liquid mouth 2 department and carrying out secondary welding and sealing, helium can't escape to the space between repair welding piece 4 and plug 5 from plug 5, so can't effectively detect repair welding piece 4 and whether accomplished the sealed of annotating the liquid mouth.
In addition, in the use of follow-up lithium cell, also can have because of the sealed condition of inefficacy of plug 5, for example because of electrolyte is after release lithium ion and pole piece take place chemical reaction, can produce complicated gas, the increase of battery internal pressure makes plug 5 outwards inflation relax and leads to plug 5 unable normal seal, or plug 5 receives the corrosive effect of electrolyte and ageing and lead to plug 5 unable normal seal etc. if repair welding lug 4 has the bad condition of welding during this, and cause the battery to reveal, not only can influence the normal use of battery, also there is the hidden danger of burning explosion simultaneously.
Therefore, it is necessary to provide a method of detecting airtightness at the repair-bonding sheet 4.
The invention provides an air tightness detection method which can be used for detecting the air tightness of a welding seal when one end of a through hole of a workpiece to be detected is welded and sealed. Firstly, placing the air bag sealed with the tracer gas in the through hole, welding one end of the through hole, and sealing one end of the through hole by adopting a sealing element. Because the welding seal can generate a large amount of heat, the air bag is fused, so that the through hole is filled with the tracer gas, and then the gas leakage of the workpiece to be detected is detected for the first time, so that the welding seal air tightness is judged. Meanwhile, an acute angle can be designed on the repair welding sheet to puncture the air bag, so that the through hole is filled with the tracer gas. However, if the airbag is not broken, a false detection may occur. Thus, the seal is broken and a second leak detection is performed. And after the detection is finished, the sealing piece is removed to judge whether the air bag is damaged or not, so that the detection omission is prevented. Specifically, if the trace gas is not detected in the first gas leakage detection and the trace gas is detected in the second gas leakage detection, the air tightness of the through hole is good; if the trace gas is detected by the first gas leakage detection, the air tightness of the through hole is poor; if the trace gas is not detected in the first gas leakage detection, the trace gas is not detected in the second gas leakage detection, and the air bag is not broken, the air tightness of the through hole cannot be judged, and the steps are repeated.
In certain embodiments of the invention, the tracer gas is selected from at least one of nitrogen, hydrogen, helium, neon, argon, krypton, xenon, or radon. Preferably, the tracer gas is helium. The skilled person will understand that the tightness detection may also be performed with other gases.
In some embodiments of the present invention, the material of the airbag includes one of PP, PE, PVC, or PS or a composite material made of the above materials. Those skilled in the art will appreciate that the material of the bladder should be chemically stable, non-reactive with the cell, and easily destroyed.
In some embodiments of the present invention, the repair welding piece used for the welding seal comprises a metal repair welding piece or a plastic repair welding piece. As can be understood by those skilled in the art, the use of metal repair welding sheets has the advantages of mature welding process, low cost and high efficiency.
In certain embodiments of the present invention, the metal patch includes one of an aluminum patch, an iron patch, or a copper patch. It will be appreciated by those skilled in the art that the present invention may be practiced with other types of patch panels.
In certain embodiments of the invention, the seal comprises a glue, gel, staple, or plug seal. Those skilled in the art will appreciate that the present invention may be practiced with other seals.
In certain embodiments of the invention, the method of detecting a tracer gas comprises helium detection. Helium detection is the most sophisticated means of detecting hermeticity available, as will be appreciated by those skilled in the art.
Example 1
Referring to fig. 1 and 2, a PP gas bag 3 filled with helium is placed into a liquid injection port 2 of a square lithium battery cover plate 1, a liquid injection hole 6 at the lower end is sealed by a rubber plug 5, an aluminum soldering lug 4 is welded and sealed at the upper end, the gas bag 3 is melted by heat generated during welding and releases the helium, and then the square lithium battery cover plate 1 is used in special equipment to detect whether the helium exceeds the standard. If the detected helium exceeds the standard, the air tightness of the welding seal is poor. If the helium is not detected to exceed the standard, a needle is inserted into the rubber plug 5 to form a gap, the square lithium battery cover plate 1 is vacuumized in special equipment, whether the helium exceeds the standard is detected again, if the helium exceeds the standard, the air tightness of the welding seal is good, and if the helium does not exceed the standard, the sealing piece is removed, and whether the air bag is damaged is checked. If the air bag 3 is not damaged, the airtightness of the weld seal cannot be determined, and the weld seal needs to be welded again and tested.
Example 2
Referring to fig. 1 and 2, an air bag 3 filled with helium is placed into a liquid injection port 2 of a square lithium battery cover plate 1, a liquid injection hole 6 at the lower end is sealed by a rubber plug 5, a repair welding sheet 4 with an acute angle is designed at the upper end to crush the air bag 3, then the air bag is sealed by welding, the air bag is punctured by the acute angle and the helium is released, and then the square lithium battery cover plate 1 is used in special equipment to detect whether the helium exceeds the standard. If the detected helium exceeds the standard, the air tightness of the welding seal is poor. If the helium is not detected to exceed the standard, a needle is inserted into the rubber plug 5 to form a gap, the square lithium battery cover plate 1 is vacuumized in special equipment, whether the helium exceeds the standard is detected again, if the helium exceeds the standard, the air tightness of the welding seal is good, and if the helium does not exceed the standard, the sealing piece is removed, and whether the air bag is damaged is checked. If the air bag 3 is not damaged, the airtightness of the weld seal cannot be determined, and the weld seal needs to be welded again and tested.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (8)
1. A method for detecting air tightness is characterized in that:
the method comprises the following steps:
s1, sealing one end of a through hole of a workpiece to be tested by adopting a sealing element, placing an air bag sealed with trace gas in the through hole, and welding the other end of the through hole;
s2, performing first air leakage detection on the workpiece to be detected;
s3, loosening the sealing element to enable the end not to have sealing performance, and performing secondary air leakage detection on the workpiece to be detected;
s4, collecting results of the first air leakage detection and the second air leakage detection;
and S5, removing the sealing element, collecting the state information of the air bag and judging the air tightness of the welding and sealing position of the through hole.
2. The airtightness detection method according to claim 1, wherein:
one end of the through hole is provided with a liquid injection port, and the other end of the through hole is provided with a liquid injection hole;
the liquid injection port is sealed by welding, and the liquid injection hole is sealed by adopting a sealing element;
the method for judging the air tightness of the through hole welding seal position comprises the following steps:
if the trace gas is not detected in the first gas leakage detection and the same workpiece is subjected to second gas leakage detection, namely the trace gas is detected only after the sealing state of the end face of the liquid injection hole is damaged, the gas tightness of the welding and sealing position of the through hole is good;
if the trace gas is detected in the first gas leakage detection, the airbag is broken and the air tightness of the through hole welding seal is not good;
if the trace gas is not detected in the first gas leakage detection, the trace gas is not detected in the second gas leakage detection, and the airbag is not ruptured, the airtightness of the through hole weld seal can not be judged, and the steps S1-S5 are repeated.
3. The airtightness detection method according to claim 1, wherein:
the tracer gas is at least one of nitrogen, hydrogen, helium, neon, argon, krypton, xenon or radon.
4. The airtightness detection method according to claim 1, wherein:
the material of the air bag is a composite material formed by one or more of PP, PE, PVC or PS.
5. The airtightness detection method according to claim 1, wherein:
the repair welding pieces adopted by the welding seal comprise metal repair welding pieces or plastic repair welding pieces.
6. The airtightness detection method according to claim 5, wherein:
the metal patch includes one of an aluminum patch, an iron patch, or a copper patch.
7. The airtightness detection method according to claim 1, wherein:
the seal comprises a glue, gel, staple or plug seal.
8. The airtightness detection method according to claim 1, wherein:
the method for detecting the air leakage comprises helium detection.
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| CN202110102504.4A CN112747868B (en) | 2021-01-26 | 2021-01-26 | Air tightness detection method |
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| CN113358291A (en) * | 2021-06-22 | 2021-09-07 | 湖北亿纬动力有限公司 | Battery cell and battery cell air tightness detection method |
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| JP2003240668A (en) * | 2002-02-20 | 2003-08-27 | Honda Motor Co Ltd | Leakage testing device |
| CN106654354A (en) * | 2016-11-29 | 2017-05-10 | 天津中聚新能源科技有限公司 | Lithium-ion battery and package detection method thereof |
| CN108692888B (en) * | 2018-06-05 | 2019-11-19 | 广舜检测技术（上海）有限公司 | A kind of method for conducting leak test of battery liquid-filling mouth enclosuring structure |
| CN108827552B (en) * | 2018-06-08 | 2020-07-17 | 合肥国轩高科动力能源有限公司 | System and method for detecting sealing performance of lithium battery after liquid injection |
| CN108956026A (en) * | 2018-09-18 | 2018-12-07 | 博众精工科技股份有限公司 | Overhead welding air tightness detection system |
| CN210607526U (en) * | 2019-08-22 | 2020-05-22 | 合肥国轩高科动力能源有限公司 | A glue nail for lithium ion battery gas leakage detection |
| CN210837928U (en) * | 2019-09-23 | 2020-06-23 | 湖南弘毅科技有限公司 | Square lithium battery |
| CN210837981U (en) * | 2019-09-23 | 2020-06-23 | 湖南弘毅科技有限公司 | Soft package lithium battery |
| CN110954278A (en) * | 2019-12-02 | 2020-04-03 | 江门龙浩智能装备有限公司 | Leak detection method |
| DE202020105226U1 (en) * | 2020-09-10 | 2020-09-17 | Thyssenkrupp Ag | Testing device for leak testing of a tub-like component |
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